In 1803, encouraged by the Peace of Amiens which provided a break in hostilities with France, his mother and stepfather took him on a European Tour.

He married at Lambeth, on 18 July 1807, a great heiress, Georgiana Elizabeth, daughter of Edward Miller Mundy of Shipley, Derbyshire.

[1] On 22 March 1821, Newcastle published a pamphlet in the form of a letter to Lord Liverpool, protesting against a Bill for Catholic Emancipation.

Secondly, the government could not be neutral on this question because if the Bill passed Parliament, the King would have to refuse Royal Assent as it would be in breach of his promise, made in the Coronation Oath, to uphold the Protestant constitution.

[6] Newcastle wrote to Lord Colchester on 15 January 1828, that he wanted "a sound, plain-dealing Protestant administration, devoid of all quackery and mysterious nonsense".

Wellington "may be the victim of a monstrous error" but he had supported relieving the Dissenters and his first parliamentary session was "by far the most disastrous of any in the memory of man".

[12] In response to further evictions, The Times rebuked Newcastle for acting like the recently deposed Charles X of France in abusing his power and claimed that his actions were the best argument in favour of reform.

Nottingham Castle was burnt to the ground and his residences at Clumber Park, Nottinghamshire and Portman Square, London also had to be fortified against the mob.

[1] In 1839, Newcastle objected to the appointment to the magistracy of two gentlemen nominated by the government, but of whose political and religious principles he disapproved (being Dissenters).

Charles Greville wrote in his diary on 2 May: I met the Duke of Wellington at the Ancient Concert, and asked him the reason, which he told me in these words: "Oh, there never was such a fool, as he is; the Government have done quite right, quite right, they could not do otherwise".

[14]On 18 July 1807 Pelham-Clinton married Georgiana Elizabeth, the only child and heiress of Edward Miller Mundy of Shipley Hall, and his second wife, Georgiana (née Chadwick) Willoughby (the former wife of Thomas Willoughby, 4th Baron Middleton and second daughter of Evelyn Chadwick of West Leake).

This situation was reversed, however, in 1949 when All Saints, West Markham, was reinstated as the parish church, and the Duke's mausoleum was left to decay.

[15] The papers of the 4th Duke, including his very detailed personal diaries for the period 1822–1851, are now held by Manuscripts and Special Collections at the University of Nottingham.